Evaluation of clinical and immunological criteria of the effectiveness of intravitreal injection of ranibizumab at macular edema due to retinal vein occlusion

Branch retinal vein occlusion (BRVO) leads to retinal ischemia, releases vascular endothelial growth factor (VEGF) and other cytokines that damage to the blood retinal barrier which causes to macular edema. The aim of the study was to determine the serum and the lacrimal fluid (LF) levels of VEGF-A and IL-6 in their association with clinical parameters in patients with BRVO on the background of ranibizumab treatment. Materials and methods: 32 patients (median age 58.9 years, women - 21) underwent a three month intravitreal ranibizumab injection (IRI) due to macular edema causes BRVO. Ophthalmological examination and spectral domain optical coherence tomography was performed every month. Serum and the LF levels of VEGF-A and IL-6 were measure by ELISA before and after 3 months of treatment with IRI. The control group consist of healthy volunteers in the same age. Results: The visual acuity was improved on the background of the three IRI to 0.3 (±0.1) by Snellen in nonischemic type and 0.15 (±0.04) in ischemic type BRVO. Reduction of the retinal thickness in the macula was obtained in both groups. The serum (714.6±311 pg/ml) and LF level (762.6±432 pg/ml) of VEGF-A were in 2 times higher than in a con-trol and significantly correlated (p=0.0001) with retinal thickness. The serum level of IL-6 was higher than in control in ischemic type BRVO. Ranibizumab treatment resulted to decrease serum and LF level of VEGF-A in all patients in correlation with clinical parameters. LF level of IL-6 was decreased in while non-ischemic type of occlusion. Conclusions: There were determined high serum and lacrimal fluid levels of VEGF-A correlated with retinal thickness in patients with macular edema due to BRVO. Intravitreal ranibizumab injections led to reduced VEGF-A in serum and tear, correlating with improvement in clinical parameters.